Prevent ambiguous overload resolution

Author: SylvainCorlay

.appveyor.yml

@@ -22,7 +22,7 @@ install:
   - conda update -q conda
   - conda info -a
   - conda install gtest cmake -c conda-forge
-  - conda install pytest numpy pybind11==2.2.4 xtensor==0.20.8 -c conda-forge
+  - conda install pytest numpy pybind11==2.4.2 xtensor==0.20.8 -c conda-forge
   - "set PYTHONHOME=%MINICONDA%"
   - cmake -G "NMake Makefiles" -D CMAKE_INSTALL_PREFIX=%MINICONDA%\\Library -D BUILD_TESTS=ON -D PYTHON_EXECUTABLE=%MINICONDA%\\python.exe .
   - nmake test_xtensor_python

include/xtensor-python/pycontainer.hpp

@@ -124,6 +124,35 @@ namespace xt
 
         PyArrayObject* python_array() const;
         size_type get_buffer_size() const;
+
+    private:
+
+#if PYBIND11_VERSION_MAJOR == 2 && PYBIND11_VERSION_MINOR >= 3
+        // Prevent ambiguous overload resolution for operators defined for
+        // both xt::xcontainer and pybind11::object.
+        using pybind11::object::operator~;
+        using pybind11::object::operator+;
+        using pybind11::object::operator-;
+        using pybind11::object::operator*;
+        using pybind11::object::operator/;
+        using pybind11::object::operator|;
+        using pybind11::object::operator&;
+        using pybind11::object::operator^;
+        using pybind11::object::operator<<;
+        using pybind11::object::operator>>;
+
+        // Prevent ambiguous overload resolution for operators defined for
+        // both xt::xcontainer_semantic and pybind11::object.
+        using pybind11::object::operator+=;
+        using pybind11::object::operator-=;
+        using pybind11::object::operator*=;
+        using pybind11::object::operator/=;
+        using pybind11::object::operator|=;
+        using pybind11::object::operator&=;
+        using pybind11::object::operator^=;
+        using pybind11::object::operator<<=;
+        using pybind11::object::operator>>=;
+#endif
     };
 
     namespace detail

test/test_pytensor.cpp

@@ -240,4 +240,26 @@ namespace xt
         auto v = xt::view(arr, xt::all());
         EXPECT_EQ(v(0), 0.);
     }
+
+    TEST(pytensor, unary)
+    {
+        pytensor<int, 1> a = { 1, 2, 3 };
+        pytensor<int, 1> res = -a;
+        pytensor<int, 1> ref = { -1, -2, -3 };
+        EXPECT_EQ(ref(0), res(0));
+        EXPECT_EQ(ref(1), res(1));
+        EXPECT_EQ(ref(1), res(1));
+    }
+
+    TEST(pytensor, inplace_pybind11_overload)
+    {
+        // pybind11 overrrides a number of operators in pybind11::object.
+        // This is testing that the right overload is picked up.
+        pytensor<double, 1> a = { 1.0, 2.0, 3.0 };
+        a /= 2;
+        pytensor<double, 1> ref = { 0.5, 1.0, 1.5 };
+        EXPECT_EQ(ref(0), a(0));
+        EXPECT_EQ(ref(1), a(1));
+        EXPECT_EQ(ref(1), a(1));
+    }
 }